This invention relates generally to calculators and improvements therein and more particularly to non-programmable scientific calculators. While many prior art calculators can perform some complex calculations involving more than one mathematical function or operation several even redundant keystrokes are usually required. The preferred embodiment of the present invention is capable of performing mathematical operations necessary to convert from one unit of measure to another with a minimum of keystokes and without the user having to look up the appropriate factor to enter into the calculator to perform the conversion.
A calculator having the features of the preferred embodiment of the present invention incorporates easily accessible conversion factors to convert measurements in inches to centimeters, in gallons to liters and in pounds to kilograms. In addition, the calculator incorporates a conversion function for converting degrees-minutes-seconds (D MS) to decimal degrees, radians or grads. These conversions and their converse accurate to ten digits are initiated by actuation of only three keys on the keyboard and without having to enter the appropriate conversion factors via the keyboard. To preserve readout accuracy when converting from decimal degrees to D MS units the calculator automatically displays the answer in fixed point notation with four digits after the decimal point ("fixed-4" notation) regardless of the display format entered or otherwise specified by the user.